Leo took the tool. He went back to his crooked tower. He found a wall where he had written “She no like apples.” It looked weak. He consulted the book. Unit 44: Do, does, did. He applied the correction. “She doesn’t like apples.” The wall suddenly straightened. The mortar dried smooth.
Cambridge University Press provides (audio and printable) for each unit on their website: Search “Essential Grammar in Use supplementary exercises” — not the main book, but free PDF samples with answers. essential english grammar in use by raymond murphy